Leaving single market and customs union is incompatible with ensuring no borders

John FitzGerald: Deal struck on Friday is ambiguous to cover fact that UK’s future course is undecided

British prime minister Theresa May and European Commission president Jean-Claude Juncker address a media conference at EU headquarters in Brussels on Friday morning. Photograph: AP

Last week’s column highlighted how, 90 years ago, Ireland’s economic relations with the UK were tied up with the future of the Border. Now, achieving a successful agreement on economic relations between the EU and the UK is entangled in the same thicket.

The Irish Government has repeatedly emphasised that the “border issue” in the Brexit talks is not about furthering Ireland’s economic interests.